This invention relates to a seat bottom extension mechanism for seats, such as aircraft passenger seats of the type found in transport aircraft. The seat has application in seats of other types as well. The seat bottom extension assembly mechanism permits adjustment of the seat bottom to offer support to the backs of the legs and knees of both relatively large and small occupants by varying the distance between the seat bottom at the bottom of the seat back (referred to as the "seat reference point" or "SRP, See, SAE Aerospace Standard AS8049, issued 1990-07, entitled "Performance Standard for Seats in Civil Rotorcraft and Transport Airplanes" ("Aerospace Standard" at 6, FIG. 1A) and the back of the knees. In so doing, the thighs of the occupant are supported along substantially the entire length from the "buttocks reference point" or "BRP" to the knee, yet the leg is permitted to bend naturally at the knee.
In the case of relatively short occupants, the seat bottom extension assembly is used in the retracted position, permitting the legs to bend naturally at the knee rather than being held in a partially unbent position by the retracted leg rest. In the case of relatively tall occupants, the seat bottom extension assembly extends, permitting the calves of the legs to be supported by the leg rest.
Substantial effort has been devoted to seat back and seat bottom design in order to promote both safety and comfort. However, prior art seats, particularly passenger seats such as aircraft passenger seats have not previously taken fully into account the length of the legs in optimizing seat comfort.